958
Inorg. Chem. 1990, 29, 958-963
510 mg, 1.27 mmol, 95.5%): mp 95 OC, IR (Nujol) 1125, 1015, 1000,
840, 315 cm-I; 'H NMR (300 MHz, CDCI,) 6 1.39 (d, 6 H), 2.05 (m, 8 H). 4.37 (m,8 H), 4.66 (septet, 1 H). Anal. Calcd for C,,H2,CI,0,Zr: C, 32.95; H, 5.79. Found: C, 31.21; H, 5.62. Preparation of the 1:4 Tetrahydrofuran Adduct of Bidentate Zirconium Trichloride Alkoxide 8. A stirred solution of the 1:2 tetrahydrofuran adduct 32bof ZrCI, (600 mg, 1.59 mmol) in dichloromethane (2 mL) was treated dropwise at 25 "C under dry N2 with a solution of the bis(trimethylsilyl) ether 71° of racemic trans- 1,2-cyclohexanediol (207 mg, 0.795 mmol) in dichloromethane ( 1 mL). The resulting mixture was stirred at 25 O C for 24 h and filtered into a test tube. A layer of pentane (3 mL) was carefully added, and the tube was kept at -25 OC for several days. This produced a crop of colorless needles contaminated with a small amount of white powder. The crystals were separated mechanically and shown by X-ray crystallography to be a 1: 1 dichloromethane solvate of the 1:4 tetrahydrofuran adduct of bidentate zirconium alkoxide 8 (400 mg, 0.453 mmol, 57.0%): mp 86-88 OC; IR (Nujol) 1160, 1090, 990, 830, 730, 315 cm-'. Anal. Calcd for C22H42C1606Zr2'CH2C12: C, 31.29; H, 5.03. Found: C, 30.29; H, 4.97. Crystallographic Data for the 1:4 Tetrahydrofuran Adduct of Bidentate Zirconium Trichloride Alkoxide 8. Crystals suitable for an X-ray study were grown by crystallization from dichloromethane/pentane. The sample selected for analysis had the following dimensions: 0.27 X 0.35 X 0.39 mm. Other crystallographic data are summarized in Table I. Crystallographic Measurements and Structure Resolution. An Enraf-Nonius CAD-4 diffractometer was used to collect a set of intensity data according to a procedure described e1~ewhere.l~Seven standard reflections checked every 1 h showed random fluctuations of less than f3.0% about their respective means. A set of 14518 Mo Ka reflections (28 5 50') was collected at 220 K over half the Laue sphere (+h, ik, ftl). Of these, 3699 ( I 5 3 4 4 ) were retained for structure resolution and refinement after averaging to Laue 2/m symmetry. These measurements were corrected for the Lorentz effect and polarization but not (14) Belanger-Garitpy, F.; Beauchamp, A. L. J . Am. Chem. Soc. 1980,102, 346 1-3464.
for absorption. The structure was solved by using direct methods (EEES) and difference-Fourier calculations (SHELX), and it was refined on IFoI by full-matrix least-squares procedures. All non-hydrogen atoms were refined anisotropically. For disordered CH2CI2,occupancies were initially refined by using common isotropic temperature factors, and then the occupancies were fixed and anisotropic temperature factors were used. Refinement converged to R = 0.042 and R, = 0.042, and the goodness-of-fit ratio S was 1.88 for 407 parameters refined. The final A F map was essentially featureless, with a general background below f0.20 e seven peaks of 0.25-0.37 e within 0.94 8, from Zr, and four peaks of 0.21-0.23 e within 1.2 8, from CI. The scattering curves for the non-hydrogen atomslS and hydrogen atoms16 were taken from standard sources. Contributions of Zr and CI to anomalous dispersion were included." Selected interatomic distances and bond angles are listed in Table 11, and atomic coordinates and isotropic temperature factors are provided in Table 111. Tables of anisotropic temperature factors and structure factors are included as supplementary material.
Acknowledgment. This work was funded by the Natural Sciences and E?gineering Research Council of Canada, by t h e Ministtre d e 1'Education du Quibec, and by Merck Frosst. In addition, we a r e grateful to Sylvie Bilodeau of t h e Regional High-Field NMR Laboratory for helping us record our lowtemperature 'H NMR spectra. Supplementary Material Available: For the 1:4 tetrahydrofuran adduct of bidentate zirconium trichloride alkoxide 8, Table SI, containing anisotropic temperature factors (2 pages); Table SII, containing structure factors (24 pages). Ordering information is given on any current masthead page. (15) Cromer, D. T.; Waber, J. T. Acta Crysrallogr. 1965, 18, 104-109. (16) Stewart, R. F.; Davidson, E. R.; Simpson, W. T. J . Chem. Phys. 1965, 42, 3175-3187. (17) Cromer, D. T.; Liberman, D. J . Chem. Phys. 1970, 53, 1891-1898.
Contribution from the Department of Chemistry, Texas A & M University, College Station, Texas 77843-3255
New Low-Dimensional Zinc Compounds Containing Zinc-Oxygen-Phosphorus Frameworks: Two-Layered Inorganic Phosphites and a Polymeric Organic Phosphinate Minghuey Shieh, Kevin J. Martin, Philip J. Squattrito, and Abraham Clearfield* Received June 12, 1989
Two new zinc phosphites have been prepared by reaction of zinc chloride with either calcium or strontium phosphite in aqueous phosphorous acid. The compounds have been characterized by single-crystal X-ray diffraction techniques. Z ~ I C ~ ( H P O ~ ) ~ ( H ~ O ) ~ : P 2 , / n , a = 7.131 (2) A,b = 7.766 (2) A, c = 14.479 (2) A, 0 = 97.30 (2)O, V = 795.3 (3) A', Z = 4, R(Fo) = 0.045 for 1063 observations ( I > 3 4 I ) ) and 109 variables. Z ~ S T ( H P O ~ ) ~ ( HPi, ~ Oa) ~=: 7.728 (2) A, 6 = 7.967 (2) A, c = 7.448 (2) A, a = 99.56 (2)O, 0 = 107.93 (2)O, y = 100.51 (2)O, V = 416.6 (2) A', Z = 2, R(FJ = 0.034 for 1187 observations ( I > 3 4 4 ) and 109 variables. Both compounds have layered structures in which the zinc atoms are tetrahedrally coordinated and the Ca or Sr atoms are 8-coordinate. In each case, the interlayer region is lined with water molecules coordinated to the alkaline-earth-metal ion. The modes in which Ca and Sr bridge the phosphite groups are different, however, resulting in layers with different topographies. These results, together with earlier work on Na+, K', and Ba2+,are discussed in terms of the effect of the alkali or alkaline-earth metals on the observed structural trends. A new polymeric zinc phenyl hosphinate has also been synthesized and its structure determined. Crystal data for Zn(O,PHC,H,),: C2/c, a = 15.763 (2) 6 = 11.162 (2) A, c = 8.272 (2) A, p = 109.34 (2)O, V = 1373.2 (6) A3, Z = 4, R(Fo)= 0.047 for 480 observations ( I > 3a(4) and 105 variables. The structure is compared with known phosphinates and phosphonates.
1,
Introduction As a n outgrowth of our continuing interest in transition-metal phosphates with framework structures,'s2 we recently reported t h e synthesis of a novel series of zinc phosphites containing alkali or alkaline-earth metals3 Each of t h e compounds prepared (containing Na+, K+, and Ba2+, respectively) had a different structure t h a t was highly dependent on t h e coordination requirements of
*To whom correspondence should be addressed 0020-1669/90/ 1329-0958$02.50/0
the alkali- or alkaline-earth-metal ion. In order to further examine the structural trends in these materials, we have prepared and characterized two new zinc phosphites of calcium and strontium. In addition, we have been exploring the chemistry of organic derivatives4-' of layered transition-metal phosphates and recently (1) Clearfield, A. Chem. Reu. 1988, 88, 125-148 and references therein. (2) Inorganic Ion Exchange Materials; Clearfield, A,, Ed.; CRC Press: Boca Raton, FL, 19821 (3) Ortiz-Avila, C. Y.; Squattrito, P. J.; Shieh, M.; Clearfield, A . Inorg. Chem. 1989, 28, 2608-2615.
0 1990 American Chemical Society
N e w Low-Dimensional Zinc Compounds
Inorganic Chemistry, Vol. 29, No. 5, 1990 959
described several new phosphonates* and organic phosphates9 of zinc. Of late, these studies have been extended t o the corresponding phosphinates. W e report here the synthesis and structure of zinc phenylphosphinate, Zn(O,PHC,H,),, and the phosphites Z I I C ~ ( H P O ~ ) ~ ( Hand ~ OZ)n~S r ( H P 0 3 ) 2 ( H 2 0 ) 2 .These results a r e discussed in the context of our earlier findings.
Experimental Section Syntheses. ZnCa(HP0,),(H20),. A 0.67-g sample of ZnCI, (Mallinckrodt reagent grade, used as received) was added to a solution of 1.20 g of CaHP03.H20 (prepared from Ca(OH), and H,PO, according to ref IO) in IO mL of aqueous 1 M H3P03 (Aldrich, 99%). The clear solution was stirred overnight, followed by the addition of 7 mL of EtOH. Colorless platelike crystals suitable for X-ray analysis were obtained after the solution had been allowed to stand for several days at room temperature. A thermogravimetric analysis of the sample was performed on a Cahn RH electrobalance. The observed weight loss (onset, 130 "C; completion, 3 IO "C) of 1 I .94% is consistent with loss of 2 mol of water per formula unit (calculated 11.95%). Z ~ I S ~ ( H P O , ) ~ ( H ~AO 0.67-g ) ~ . sample of ZnCI, was added to a solution of 1.67 g of SrHP03.H20(prepared from SrCO, and H3P03as described in ref IO) in 12 mL of aqueous 1 M H3P03. The resultant solution was stirred for 2 days, after which 3 mL of EtOH was added. Small colorless platelets grew from the solution, which was allowed to stand at room temperature for IO days. A TGA of the crystals showed a weight loss of 10.18% between 30 and 290 O C (calculated for ZnSr(HP03)2(H20)2 on the basis of H 2 0 10.32%). Zn(02F"C6H5)2. A 10-mL aliquot of 1 M ZnCll solution (0.01 mol) was added to 1.4 g of H02PHC6H5(phenylphosphinic acid) (0.01 mol) in 50 mL of aqueous 30% EtOH. A polycrystalline white solid precipitated immediately. An X-ray powder diffraction pattern of the sample is in excellent agreement with that calculated from the single-crystal structure of Zn(02PHCqH5), (vide infra). Colorless, plate-shaped crystals suitable for the single-crystal X-ray study were grown from a standing solution of 0.7 g of H02PHC,H5 (0.005 mol) and 5 mL of 1 M ZnC12 (0.005 mol) in 100 mL of water. Crystallographic Studies. All single-crystal X-ray diffraction work was performed at room temperature on a Rigaku AFC5R four-circle diffractometer equipped with a 12-kW rotating anode Mo X-ray source (X(Ka) = 0.71069 A). In each case, a suitable single crystal was mounted on a glass fiber with silicone cement. Unit cell parameters were derived from least-squares refinements of the setting angles of 25 highangle reflections (25' < 20(Mo Ka) < 50") in which the monoclinic cell angles a and y were constrained to be 90'. Intensity data were collected by using the a-28 scan technique at 16'/min (Zn(02PHC6H5)2)or Io/min (ZnCa(HP03)2(H20)2and ZnSr(HPO,),(H,O),) in w . Up to three identical scans were performed on weak data. The intensities of three standards checked at 150-reflection intervals throughout data collection displayed only small random variations. All crystallographic computations were performed on a DEC MicroVAX I1 computer with the TEXSAN'~ series of programs. Space groups were assigned on the basis of systematic absences and intensity statistics. In all cases, these led to satisfactory refinements. Each of the structures was solved by direct methods ( M I T H R I L ~The ~ ) . positions of the heavy atoms Zn, Ca, and Sr were taken from E maps, while the remaining non-hydrogen atoms were located by direct-methods phase refinement techniques (DIRDIFI3). Alberti, G.;Allulli, S.; Costantino, U.; Tomassini, N. J . Inorg. Nucl. Chem. 1978, 40, 11 13-1 117. Cunningham, D.; Hennelly, P.; Deeney, T. Inorg. Chim. Acta 1979,37, 95-102. Cao, G.; Lee, H.; Lynch, V.; Mallouk, T. Solid State Ionics 1988, 26, 63-69. Cao, G.; Lee, H.; Lynch, V.; Mallouk, T. Inorg. Chem. 1988, 27, 2781-2785. Martin, K. J.; Squattrito, P. J.; Clearfield, A. Inorg. Chim. Acra 1989, 155, 7-9. Ortiz-Avila, C. Y.; Rudolf, P. R.; Clearfield, A. Inorg. Chem. 1989, 28, 21 37-2 141.
Mellor's Comprehensive Treatise on inorganic and Theoretical Chemistry; Wiley: New York, 1971;Vol. 111, Suppl. 111, p 641 and references
therein.
TEXSAN. Texray Structural Analysis Package; Molecular Structure Corp.: The Woodlands, TX, 1987 (revised). Gilmore, G . J. MITHRIL. A Computer Program for the Automatic Solution of Crystal Structures from X-ray Data. University of Glasgow, Scotland, 1983. Beurskens, P. T. DIRDIF:Direct Methods for Difference Structures-An Automatic Procedure for Phase Extension and Refinement of Difference Structure Factors. Technical Report 1984/ I; Crystallography Laboratory: Toernooiveld, 6525 Ed Nijmegen, The Netherlands, 1984.
02'
T
H2
05
04
Figure 1. Connectivity of the various coordination polyhedra in ZnCa(HP0,)2(H20)2. Thermal ellipsoids in this and succeeding figures are shown at the 50% probability level. Hydrogen atoms are shown as isotropic spheres of arbitrary size.
Figure 2. Perspective drawing of the ZnCa(HP0,)2(H20)2 structure along [OIO], showing the layers as viewed edge-on. The bonds to zinc and phosphorus are solid black, while those to Ca are hollow.
Difference electron density maps revealed the positions of all the phosphite hydrogen atoms and all but one of those in coordinated water molecules of the Ca compound. The water protons could not be located in the Sr compound, their presence probably masked by the high absorption of the material. The phenyl H atoms in Zn(O2PHC6H5),were also found via a difference Fourier synthesis and their positions refined. Final refinements for all the structures were performed on those data having I > 3a(I) and included anisotropic thermal parameters for all non-hydrogen atoms. Analyses of F, vs F, as a function of (sin 8)/A, Miller indices, and F, displayed no unusual trends. There were no peaks in the final difference electron density maps with height greater than about 3% that of the heaviest atom in any of the structures. Due to the relatively high linear absorption coefficient ( p = 42 cm-') and the anisotropic shape of the ZnCa(HP03)2(H20)2crystal (approximate dimensions 0.30 X 0.30 X 0.02 mm), the absorption effects for this compound are not negligible. In the absence of an absorption correction, the thermal ellipsoids are elongated along the stacking axis (Figure 2). Summaries of the X-ray experiments and crystal data for the three compounds are given in Table I. Final positional and equivalent isotropic thermal parameters are listed in Table 11, while selected bond distances
960 Inorganic Chemistry, Vol. 29, No. 5, 1990
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Table 1. Crystallographic Data for New Zinc Compounds ZnCa(HPOMHzOh a 7.131 (2)8, space group: P21/n (No. 14) b = 7.766 (2)8, T = 23 OC c = 14.479 (2)A X = 0.71069 A 4 = 91.30 (2)' paid = 2.52gem-' V = 195.3(3)AS w = 41.96 cm-' 2-4 R(Fo) = 0.045 fw 301.45 R,(F,) = 0.058 =i
ZnSr(HP03)2(H20)2 space group: PT (No. 2) T = 23 OC b = 7.967 (2)8, X = 0.71069A c = 7.448 (2)8, paid = 2.78 gem-' a = 99.56(2)' p = 95.46 cm-' 6 = 107.93 (2)O transm coeff = 0.305-1.0 y = 100.51 (2)' R(Fo)= 0.034 V = 416.6 (2)A3 z = 2 Rw(Fo)= 0.049 fw 348.99 a
= 7.728 (2) A
Zn(O2PHC6H& space group: C2/c (No. 15) b = 11.162 (2) 8, T = 23 O C c = 8.272 (2)A X = 0.71069 8, pCalcd = 1.68 gcm-' (3 = 109.34(2)O V = 1373.2 (6)A' fi = 20.65 cm-I z = 4 R(Fo) = 0.047 fw 347.55 Rw(Fo)= 0.052 a = 15.763 (2)A
33
Figure 3. Connectivity of the polyhedra and atom-labeling scheme in ZnSr( HP03)2(H,O),.
and angles appear in Table 111. Tables of crystallographic details and anisotropic thermal parameters (Table SI) and structure amplitudes (Table S11) are available as supplementary material.
Results and Discussion Z I ~ C ~ ( H P O ~ ) ~ (The H ~ structure O)~ is shown in Figures 1 and 2. The Zn atoms are i n a very regular tetrahedral coordination (Table 111) of oxygen atoms supplied by four different phosphite groups. The Zn and P tetrahedra are bridged by the C a atoms to form the novel two-dimensional layer structure shown in Figure 2. All the phosphite oxygen atoms interact with Ca except 0(2), which bridges only P( 1 ) and Zn. Of the remaining five, four are triply bridging, coordinating either to Zn and C a (0(l ) , 0(4), J and O ( 5 ) ) or to two C a atoms (0(8)), while O(3) is doubly a bridging, linking just P(2) and Ca. Thus the phosphite groups Figure 4. Edge-on view of the layers in ZnSr(HP03)2(H20)2.Bonds to both chelate and bridge Ca while only bridging Zn. The Ca atoms Zn and P are solid black, while those to Sr are hollow. sit in a distorted square antiprism (Figure 1) consisting of six phosphite oxygen atoms and two coordinated water molecules. and by US.^ These materials contain M-03P layers propped apart There are six short C a - 0 distances ranging from 2.376 (5) to by the R groups, which are directed into the interlayer region. 2.452 (6) and two long distances of 2.722 (6) and 2.984 (7) Z I I S ~ ( H P O ~ ) ~ ( H ~AsOthe ) ~ . chemical behavior of Sr is very A. The bonds to the water molecules (atoms O(6)and O(7)) are similar to that of Ca, it was of interest to prepare the corresponding among the shorter distances. This type of 8-fold coordination for strontium zinc phosphite. The resultant compound has the same Ca is also found in phosphates such as Ca(H2P04)2.H20i4(da-0 formula but a layered structure different from that of the calcium = 2.30-2.74 A). In the best known calcium-containing phosphates, zinc phosphite. As shown in Figure 3 and Table 111, the Zn the apatite family, Ca takes a 9-fold coordination, again with a coordination is again a nearly regular tetrahedron of oxygen atoms wide range (ca. 2.30-3.00 A) of C a - 0 distance^.'^ from four different phosphite groups. The Sr atoms are in an The most interesting features of this material are the lamellar irregular 8-fold coordination that is intermediate between a square structure and the presence of the interlayer region, which is lined antiprism and a dodecahedron. As for Ca, the Sr coordination with the hydrogen atoms of the phosphite groups and coordinated sphere contains six phosphite oxygen atoms and two coordinated water molecules, There are no apparent hydrogen-bonding inwater molecules ( O ( 7 )and O(8)). The Sr-0 distances (2.533 teractions between the layers. As the calcium ions are an integral (4)-2.760 (5)A) are more regular than the C a - 0 distances and part of the layers, we would not expect them to be active with are in good agreement with reported values in strontium phosrespect to ion exchange. However, the protons on the oxygen phates.I6 As in the Ca compound, the phosphite groups both atoms bound to the electropositive CaZ+ions may be somewhat chelate and bridge Sr while only bridging Zn; however, here the acidic and thus may be mobile either in the solid state or in contact pattern is different. Only four of the six independent phosphite with aqueous solution (in which the compound is insoluble). The oxygen atoms are bridged by the Sr atom. All of these are chemical and physical properties of this material are currently 3-coordinate: O ( 5 ) and O(6) bridge two Sr atoms while O(1) under investigation. and O(4) coordinate to both Zn and Sr. Atoms O(2) and O(3) Given the structural relationship of the phosphite group to the are 2-coordinate, bridging between Zn and P(2) and P( l ) , rephosphonates, in which the H atom is replaced by a n organic R spectively. This change in connectivity alters the layers and thus group, this compound can also serve as a model for new classes the nature of the void in the Sr compound. As may be seen in of layered phosphonates of the type reported recently by M a l l ~ u k ~ ~ ~Figure 4,one of the phosphite groups juts out into the interlayer (14) MacLennan, G.; Beevers, C . Acra Crysrallogr. 1956,9, 187-190. (15) Posner, A.: Perloff, A.: Diorio, A. Acra Crysfallogr. 1958, ! I , 308-309.
(16) Boudjada, A,: Masse, R.; Guitel, J. Acra Crysrallogr., Secf. B 1978, 34, 2692-2695.
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Zinc Compounds
Inorganic Chemistry, Vol. 29, No. 5, 1990 961
Table 11, Positional Parameters and Equivalent Isotropic Thermal Parameters atom X Y z BMaaA2 Zn Ca P(l) P(2) O(1)
O(2) O(3) O(4) O(5) O(6) O(7) O(8) H(1) H(2) H(3) H(4) H(5) Sr Zn P(l) P(2) O(1)
O(2) O(3) O(4)
O(5) O(6) O(7) 0(8) H(1) H(2) Zn P O(1)
O(2) C(1) C(2) C(3) C(4) C(5) C(6) H(1) H(2) H(3) H(4) H(5) H(6)
0.3768 ( I ) 0.4815 (2) 0.2695 (3) 0.0824 (3) 0.2440 (7) 0.6332 (7) 0.5290 (7) 0.261 ( I ) 0.3284 (7) 0.7468 (7) 0.5742 (8) 0.6448 (8) 0.1189 -0.0090 0.7608 0.8407 0.7101
ZnCa(HPOd2(H20)2 0.0734 ( I ) 0.85887 (6) 0.5567 (2) 0.8679 ( I ) 0.8035 (2) 1.0067 (1) 0.3747 (2) 0.8186 (1) 0.2862 (6) 0.8819 (3) 0.0703 (6) 0.9213 (4) 0.7595 (7) 0.7501 (4) 0.9072 (4) -0.1311 (7) 0.0282 (6) 0.7250 (3) 0.7286 (7) 0.9248 (3) 0.3533 (8) 0.7569 (4) 0.3753 (6) 0.9866 (4) 0.801 5 1.0207 0.8714 0.4090 0.9768 0.7121 0.8962 0.7208 0.3231 0.7415
0.28416 (8) 0.2768 (1) 0.3293 (2) 0.0199 (2) 0.2146 (6) -0.1248 (6) 0.4692 (6) 0.2654 (7) 0.3973 (6) 0.0296 (6) 0.2248 (8) 0.5048 (7) 0.1993 0.0453 'I2
0.6149 (2) 0.5943 (5) 0.5553 (5) 0.7296 (8) 0.7870 (9) 0.8756 (9) 0.908 ( I ) 0.853 ( I ) 0.7647 (9) 0.605 (7) 0.770 (9) 0.907 (8) 0.961 (8) 0.874 (8) 0.729 (7)
ZnSr(HP03)2(H20)2 0.02229 (8) 0.6076 (1) -0.4852 (1) 0.5746 (1) 0.2217 (2) 0.2660 (3) -0.3264 (2) 0.2755 (3) -0.3180 (6) 0.4196 (8) -0.4912 (6) 0.2628 (7) 0.3700 (6) 0.2393 (7) 0.2851 (6) 0.4342 (7) 0.2957 (8) 0.0574 (6) 0.6729 (7) 0.1555 (6) 0.8679 (8) -0.1339 (7) 0.8674 (8) 0.2960 (7) 0.1788 0.1 152 -0.3432 0.1167 Zn(02PHC6Hd2 0.0588 (2) '14 -0.1410 (3) 0.5212 (4) 0.407 (1) -0.0341 (9) 0.1618 (8) 0.129 (1) -0.131 (1) 0.656 ( I ) 0.639 (2) -0.040 (1) -0.036 ( I ) 0.748 (2) 0.870 (2) -0.121 (2) 0.891 (2) -0.211 (2) -0.214 ( I ) 0.784 (2) -0.23 ( I ) 0.41 (1) 0.01 ( I ) 0.59 (2) 0.02 (1) 0.73 (2) 0.93 (2) -0.11 (1) -0.28 ( I ) 0.96 (2) -0.27 ( I ) 0.79 (1)
B , = 4/3[a2&1+ b2@22 + c2&,
+ (2bc COS ~1)/323].
1.25 (4) 1.16 (6) 1.00 (7) 0.97 (7) 1.4 (2) 1.4 (2) 1.6 (2) 2.4 (2) 1.3 (2) 1.6 (2) 2.2 (2) 1.7 (2) 1.2 1.1
1.9 1.9 2.6 1.21 (2) 1.43 (3) 1.15 (5) 1.22 (5) 1.9 (2) 1.8 (2) 1.7 (2) 1.9 (2) 1.9 (2) 1.6 (2) 2.4 (2) 2.4 (2) 1.3 1.4 1.8 (1) 2.3 (2) 3.8 (4) 2.5 (4) 2.0 (5) 3.0 (7) 3.7 ( 7 ) 3.9 ( 7 ) 3.7 (7) 2.8 (6) 2.8 3.2 4.4 4.5 4.5 3.3
+ (2ab cos y)BI2+ (2ac cos fl)bl3
region, appearing to partition the gap into channels parallel to [ l o o ] . T h e effect of this different topography is evident in the repeat distances between the layers in the two compounds. In the C a phase, in which the layers are parallel to (101), it is ca. 6.05 A, while, in the Sr compound (layers parallel to (1 lo)), it is 1.49 A. We have now synthesized from aqueous solution a series of zinc phosphites containing alkali or alkaline-earth-metal ions. The structures of the phases Zn3Na2(HP0,),, Z I I , K ~ ( H P O ~ )and ~, Z n 3 B a ( H P 0 3 ) 4 ( H 2 0 ) 6were described in an earlier report.3 The results for these compounds, together with Z n C a ( H P 0 3 ) 2 ( H 2 0 ) 2 and Z I I S ~ ( H P O , ) ~ ( H ~ Oare ) ~ summarized , in Table IV in terms of the coordination behavior of the group I and I1 metal ions. As expected, the coordination numbers ( C N ) increase with ionic radius and charge. This increase is accomplished by inclusion of increasing numbers of water molecules in the coordination sphere. Also, the manner in which the ions bridge the phosphite groups changes with ionic size. Thus, though the N a + and K+ compounds have the same composition, they have different
Figure 5. Perspective view of the Zn(02PHC6H5)2 structure along [OOI] showing the atom-labeling scheme. Phenyl hydrogen atoms have been omitted. Bonds to Zn are shown in solid black.
structures, with the Z I I , K ~ ( H P O , ) ~framework possessing small tunnels that are absent from the Z n 3 N a 2 ( H P 0 J 4 structure. The reason for this difference is evident in the M-0 bond distances in Table IV, which correspond to the differences in ionic radii of N a + and K+. It is perhaps surprising that Ca2+ and Sr*+,which are much closer in size, should also yield heteromorphic structures. Here, too, the difference in ionic radii is reflected in the M-0 distances and the resulting polyhedral connectivities. On going from group I to group 11, there is a clear change in behavior as well. Whereas the compounds containing the monovalent ions have compact three-dimensional structures with no water, those of the divalent ions are two-dimensional (Le., layered) with large open spaces lined with water molecules. This trend continues with the Ba2+ structure, which has a pattern of crisscrossing layers that form large channels. That the divalent ions form more open structures may be due in part to their tendency to favor chelation by the phosphite ions and inclusion of water molecules in the coordination sphere. It is clear that in the Zn-M-HPO, ( M = group I or I1 metal) system, the M ion is the key factor in determining the type of structure that crystallizes from aqueous solution. In each case, the tetrahedral H P 0 3 * - ions are bridged by the Zn2+ ions so as to give zinc a regular tetrahedral coordination. It is the manner in which the M ion bridges these tetrahedra that fixes the nature of the framework. These results suggest a great diversity of structures in as yet unexplored systems. Moreover, as the phosphite ion represents a rigid building block, it should be possible to predict the types of structures that will form primarily from a knowledge of the coordination behavior of the metal ions in similar systems. Zn(02PHC6H5)z.The structure, shown in Figure 5 , consists of isolated ( Z n ( 0 2 P H C 6 H 5 ) 2 ) ,chains running parallel to the c axis. The phosphinate groups bridge alternate zinc atoms in a zigzag pattern in the b-c plane. The zinc coordination is tetrahedral with regular bond distances and angles. Each of the oxygen atoms in the zinc coordination sphere is from a different phosphinate group, and so, there is no chelation to zinc in this compound. The oxygen atoms are 2-coordinate, bridging just Zn and P. As might be expected, the O(l)-P-O(2) angle has opened
962 Inorganic Chemistry, Vol. 29, No. 5, 1990
Shieh et al.
Table 111. Selected Interatomic Distances (A) and Angles (deg)
Zn-O(2) Zn-O( 1 ) Zn-0(5) Zn-0(4) P(I)-H(1) O(2)-Zn-O( I ) O(2)-Zn-0( 5) 0(2)-Zn-0(4) O( I)-Zn-0(5) O( I)-Zn-0(4) O( S)-Zn-0(4) H( 1)-P( 1 )-O(8) H( 1)-P( 1 )-0(4) H( 1 )-P( I )-0(2) O(8)-P( 1 )-0(4) O(8)-P( 1)-0(2) O(4)-P( 1)-0(2)
Zn-O(4) Zn-O( I ) Zn-O( 2) Zn-O( 3) P(1)-H(I) 0(4)-Zn-0( I ) 0(4)-Zn-0( 2) O(4)-Zn-0( 3) O( I)-Zn-0(2) O( I)-Zn-0(3) 0(2)-Zn-O( 3) H( I)-P( 1)-0(5) H( l)-P(l)-O(4) H( I)-P( 1)-0(3) O(5)-P( 1)-0(4) O(5)-P( 1)-0(3) O(4)-P( l)-0(3)
1.934 (5) 1.955 (5) 1.957 ( 5 ) 1.960 (6) 1.118
112.4 (2) 119.9 (2) 103.8 (2) 107.0 (2) 112.9 (3) 100.3 (2) 11 1.39 104.64 104.38 109.5 (3) 113.5 (3) 113.0 (3) 1.924 (5) 1.935 ( 5 ) 1.937 (5) 1.965 (5) 1.200 116.0 (2) 109.2 (2) 111.4 (2) 111.3 (2) 104.4 (2) 103.8 (2) 106.48 1 10.43 104.49 108.2 (3) 115.6 (3) 1 1 1.5 (3)
0(2)-Zn-0(2) 0(2)-Zn-0(1) 0(2)-Zn-0(1)
1.515 ( 5 )
H(Z)-P(2)-0(3) H(2)-P(2)-0(5) H(2)-P(2)-0(1) 0(3)-P(2)-0(5) 0(3)-P(2)-0(1) O(S)-P(2)-0(1) 0(6)-Ca-0(3) 0(6)-Ca-0(8) 0(6)-Ca-0(7) 0(6)-Ca-0(5) 0(6)-Ca-0(8) 0(6)-Ca-0( 1)
106.2 (5) 107.0 (3) 110.8 (4) O(1)-Zn-O(1) 114.7 (6)
107.26 114.49 99.21 114.1 (3) 115.1 (3) 106.0 (3) 72.3 (2) 77.9 (2) 109.1 (2) 149.9 (2) 86.8 (2) 152.1 (2)
H(2)-P(2)-0(6) H( 2)-P(2)-0(2) H(2)-P(2)-0(1) 0(6)-P(2)-0(2) 0(6)-P(2)-0(1) 0(2)-P(2)-0(1) 0(6)-Sr-0(5) 0(6)-Sr-0(8) 0(6)-Sr-0( 7) 0(6)-Sr-0(6) 0(6)-Sr-0(4) 0(6)-Sr-0(1)
110.50
107.50 102.87 115.4 (3) 108.7 (3) 111.2 (3) 154.5 (2) 83.4 (2) 79.7 (2) 74.4 (2) 73.0 ( I ) 122.3 ( I ) 1.510 19) 1.79 ( I ) '
O( 1)-P-0(2)
116.7 ( 5 ) 107.9 (6) 110.1 ( 5 )
Table IV. Coordination Environments of Alkali- and Alkaline-Earth-Metal Ions in Zinc Phosphites"
radius,
Ab
ion Na+ K+ Ca2+ Sr2+ Ba2+ "a+,
1.02 1.38 1.OO
1.18
1.38
,'K
Ba2':
CN 6 7 8 8 12
bond dist to 0, A 2.389 (8)-2.904 (7) 2.652 (8)-3.262 (7) 2.376 (5)-2.984 (7) 2.533 (4)-2.760 (5) 2.876 (4)-3.053 (6)
no. of water molecules in coordn sphere 0 0
2 2 8
ref 3. Ca2+, Sr2+: this work. bReference 20.
about 7' from the ideal tetrahedral angle to accommodate the bridging arrangement. The chains pack so as to create a face-centered array in the a-6 plane. The closest nonbonded contacts between the phenyl roups are 2.8 (2) A (H(3)-H(3')) within a chain and 2.8 (3) (H(4)-H(4')) between neighboring chains. The shortest contacts within the parallel sets of rings along the chains are nearly 4 A (C(2)-C(6) = 3.83 (2) A). The polymeric nature of the Zn(02PHC&5)2 structure is, as it turns out, typical of phosphinate salts of divalent transition metals, which were widely studied in the early 1970s as so-called inorganic coordination p ~ l y m e r s . l ~ - ' ~ Thus, Z n ( 0 2 P ( n -
1
(17)
Gillman, H. lnorg. Chem. 1974, 13, 1921-1924.
0(6)-Sr-0( 5) O( 5)-Sr-0(8) O(5)-Sr-0(7) O(5)-Sr-0(6) O(5)-Sr-0(4) 0(5)-Sr-O( 1) 0(5)-Sr-0(5) 0(8)-Sr-O( 7) O(8)-Sr-0( 6) O(8)-Sr-(3(4) 0(8)-Sr-O( 1)
Z~(W'HC~HS)~ C(l)-C(2) c(2j-c(3) 1.38 (2) C(3)-C(4)
P-0(2) p-c(i j C(l)-C(6) O(l)-P-C(l) 0(2)-P-C(1)
0(6)-Ca-0(4) O( 3)-Ca-0(8) O(3)-Ca-0( 7) O( 3)-Ca-0( 5) O( 3)-Ca-0( 8) 0(3)-Ca-0( 1) O(3)-Ca-0(4) 0(8)-Ca-0(7) 0(8)-Ca-0( 5 ) O(8)-Ca-O( 8) O(8)-Ca-O( 1)
ZnSr(HPOd2(H20)2 1.521 (5) P(2)-0(2) 1.526 ( 5 ) P(2)-0(1) Sr-O(6) 1.533 ( 5 ) Sr-O( 5 ) 1.248 Sr-0(8) 1.502 ( 5 )
P(1)-0(5) P(1)-0(4) P(1)-0(3) P(2)-H(2) P(2)-0(6)
1.916 (8) 1.921 (8) 1.49 ( I )
Zn-O(2) Zn-O(l) P-O( 1 )
ZnCa(HPOMW2 P(2)-0(5) 1.521 (6) P(2)-0(1) 1.531 ( 5 ) Ca-O(6) Ca-O(3) 1.098 Ca-0(8) 1490 (5)
P(1)-0(8) P(1)-0(4) P(1)-0(2) P(2)-H(2) P(2)-0(3)
C(6)-C(I)-C(2) C(3)-C(2)-C(I) C(4)-C(3)-C(2)
1.525 ( 5 ) 1.540 ( 5 ) 2.376 ( 5 ) 2.378 ( 5 ) 2.405 ( 5 ) 83.8 (2) 143.2 (2) 83.1 (2) 82.3 (2) 125.1 (2) 135.3 (2) 74.0 (2) 86.8 (2) 131.4 (2) 73.1 (2) 75.2 (2)
1.530 ( 5 ) 1.538 (5) 2.533 (4) 2.571 ( 5 ) 2.572 (5) 122.7 ( I ) 76.7 (2) 85.3 (2) 127.9 ( I ) 115.8 (2) 74.2 (1) 77.3 (2) 91.9 (2) 154.7 (2) 74.8 (2) 150.2 (2)
1.39 (2) 1.39 (2j 1.35 (2) 117 ( I ) 120 ( I ) 121 ( I )
Ca-O(7) Ca-O(5) Ca-O(8) Ca-O(l) Ca-O(4) 0(8)-Ca-0(4) 0(7)-Ca-0( 5 ) 0(7)-Ca-0(8) 0(7)-Ca-0( 1) 0(7)-Ca-0(4) O( 5)-Ca-0(8) 0(5)-Ca-O( 1) O( 5)-Ca-0(4) O(8)-Ca-O( 1) 0(8)-Ca-0(4) O( 1)-Ca-0(4)
Sr-O(7) Sr-O(6) Sr-O(4) Sr-O(l) Sr-O(5) 0(8)-Sr-0(5) O(7)-Sr-O(6) O(7)-Sr-O(4) 0(7)-Sr-0( 1) 0(7)-Sr-O( 5) 0(6)-Sr-0(4) 0(6)-Sr-0( 1) 0(6)-Sr-0( 5) 0(4)-Sr-0( 1) 0(4)-Sr-0( 5) O( I)-Sr-0(5)
C(4)-C(5) C(5)-C(6) C(3)-C(4)-C(5) C(6)-C(5)-C(4) C(5)-C(6)-C(I)
2.405 (6) 2.447 (5) 2.452 (6) 2.722 (6) 2.984 (7) 124.0 (2) 83.0 (2) 151.4 (2) 76.7 (2) 149.0 (2) 95.0 (2) 56.2 (2) 13.6 (2) 78.6 (2) 53.2 (2) 105.4 (2)
2.580 (5) 2.626 (5) 2.639 (5) 2.709 (5) 2.760 (5) 101.2 (2) 95.7 (2) 150.7 (2) 79.6 (2) 154.9 ( I ) 87.2 (2) 55.1 (1) 81.5 ( I ) 124.3 (2) 54.4 ( I ) 78.5 ( I )
1.38 (2) 1.38 (2) 120 ( I ) 119 ( I ) 122 ( I )
C4H9)(C6H5))218 also possesses infinite chains of tetrahedral zinc atoms bridged by the phosphinate groups, and Pb(02P(C6H5)2)219 has a polymeric structure very similar to that of the present compound, except that the lead coordination is distorted to a trigonal bipyramid by a lone electron pair that occupies a n equatorial site. Analogous materials have been reported for most of the first-row transition metals;17 however structural d a t a on these compounds are lacking. The Z n ( 0 2 P H C 6 H 5 ) 2structure is distinguished from the reported structures in that it is based on a mono- rather than a bis-substituted phosphinate. The absence of the extra R group leads, as expected, to a more compact packing of the chains. The phosphinate structures may be constrasted with those of the divalent metal p h o s p h o n a t e ~ . ~ For - ~ example, zinc phenylphosphonate, Zn(03PC6H~)*H20,7'8 has a layered structure in which the Z n atoms are octahedrally coordinated by the phosphonate groups (the water molecule completes the octahedron) in both chelating and bridging modes, with the phenyl groups directed into the gap between these Z n - 0 3 P layers. Thus, the dimensionality of these simple materials is a direct function of the number of oxygen atoms available for bonding to the metal (18) Giordano, F.; Randaccio, L.; Ripamonti, A. Acta Crystallogr., Secf. B 1969, 25, 1057-1065. (19) Colamarino, P.; Orioli, P.; Benzinger, W.; Gillman, H. fnorg. Chem. 1976, 15, 800-804. (20) Shannon, R. D. Acta Crystallogr., Secf. A 1976, 32, 151-767.
963
Inorg, Chem. 1990, 29, 963-970 atoms. These results suggest that it should be possible to prepare new materials with different structures from mixed phosphonate-phosphinate or phosphite systems. This work is in progress.
Acknowledgment. W e gratefully acknowledge support for this work by the Robert A. Welch Foundation under Grant No. A673.
The single-crystal diffractometer was purchased under DOD Grant No. N-00014-86-G-0194. Supplementary Material Available: Table SI, giving experimental crystallographic details and anisotropic thermal parameters (4 pages); Table SII, listing calculated and observed structure amplitudes (29 pages). Ordering information is given on any current masthead page.
Contribution from the Dipartimento di Chimica, Universiti di Firenze, Via Maragliano 75/77, 50144 Firenze, Italy, Laboratoire de Chimie des MEtaux de Transition, UniversitE Pierre et Marie Curie, 75230 Paris, France, and Departament de Quimica Inorginica, Facultat de Quimica, Universitat de Valtncia, C/Dr. Moliner 50, Burjassot, 46100 ValEncia, Spain
Oxalato and Squarato Ligands in Nickel(11) Complexes of Tetraazacycloalkanes. Solution and Solid-state Studies. Crystal and Molecular Structures of (p-Oxalato)bis[( 1,7-dimethyl-1,4,7,l0-tetraazacyclododecane)nickel( 11)] Perchlorate Dihydrate and of Bis[diaquo( 1,4,7,10-tetraazacyclododecane)nickel(II)] Squarate Diperchlorat e Andrea Bencini,la Antonio Bianchi,**laEnrique Garcia-Espaiia,*ilb Yves Jeannin,lc Miguel Julve,*-lb Victor Marcelino,Ib and Michele Philoche-LevisallesIC Received May 12, 1989 Three new nickel(I1) complexes of formula [Ni2(Me2cyclen)20x](C104)2~2H20 (l), [Ni2(cyclen)20x](N03)2(2), and [Ni(cyc~~~)](H~O)~]~(C~O,)(CIO~)~ (3), where Me2cyclen = 1,7-dimethyl-1,4,7,10-tetraazacyclododecane,cyclen = 1,4,7,10-tetraaza1,2-dione (squarate), have been cyclododecane,ox2- = the oxalate anion, and C4O?- = the dianion of 3,4-dihydroxy-3-cyclobutenesynthesized. The crystal and molecular structures of 1 and 3 have been solved at 298 K by sin le crystal X-ray analyses. 1 crystallizes in the monoclinic system, space group P21/n, with a = 22.815 (15) A, b = 10.713 ( I ) = 7.506 (3) A, @ = 97.85 (3)O, Z = 2, and R = 0.0415. 3 crystallizes in the orthorhombic system, space group P2,cn, with a = 11.124 (3) A, b = 11.461 (3) A, c = 5.735 (6) A, Z = 4, and R = 0.0345. The structure of 1 consists of centrosymmetrical poxalato-bridged nickel(I1) binuclear units [Ni2(Me2cyclen)2~~]2+ with noncoordinated perchlorate anions and water molecules. The tetraazamacrocycle adopts a folded conformation around the nickel atom, which is 6-coordinated in an octahedral distorted arrangement: the Ni-N distances are in the range 2.050 (2)-2.154 (3) A, and the Ni-O(ox) distances are 2.095 (2) and 2.102 (2) A. The oxalate ion acts as a units and noncoordinated bis-bidentate ligand between two nickel(I1) ions. The structure of 3 is made up of [Ni(cy~Ien)(H,O)~]~+ squarate and perchlorate anions. The tetraazamacrocycle adopts a folded conformation to produce a cis-pseudooctahedralgeometry at each nickel atom. The configuration of the four nitrogen atoms is such that the hydrogen atoms attached to them are on the same side with respect to the idealized macrocyclic plane. Coordinated water molecules and squarate oxygen atoms are linked by hydrogen bonds. Intramolecular antiferromagnetic spin-exchange coupling between the two nickel(I1) ions is observed fo: comp!exes 1 (J = -34 cm-l; g = 2.30) and 2 (J = -35 cm-I; g = 2.15) ( J being the parameter of the exchange Hamiltonian H = -JsA.SB). The thermodynamic parameters of the equilibrium [Ni(L)I2+ ox2- = [Ni(L)ox] where L = cyclam, cyclen, and Me2cyclenhave been determined by potentiometric and microcalorimetric measurements in aqueous solution at 25 OC in 0.1 mol dm-' KN03. The values of AGO found for the addition of the oxalate anion to [Ni(cyclen)12+and [Ni(Me2cyclen)12+are equal within experimental error (AGO = -5.6 ( I ) and -5.7 (1) kcal mol-', respectively). A greater enthalpy of reaction has been found for [Ni(Me2cyclen)12+(AH0 = -2.9 ( I ) kcal mol-I) than for [Ni(cyclen)12+(AHo = -2.4 (1) kcal mol-'). The addition of oxalate to [Ni(cyclam)12+(69% square, 29% tram-diaquo, 2% cis-diaquo forms) is an enthalpy-driven reaction (AGO = -3.8 (1) kcal mol-l and AHo = -3.8 (1) kcal mol-'). From these values, the thermodynamic parameters for the reaction of oxalate with each one of the three forms have been calculated and discussed.
1,
+
Introduction In a recent paper,2 we have reported t h e synthesis, crystal structure, and magnetic properties of t h e mixed-ligand complex [Ni2(cyclam)20x]( N 0 3 ) 2(cyclam = 1,4,8,11 -tetraazacyclotetradecane and ox2- = oxalate anion). In this complex, oxalate acts as a bis-bidentate ligand bridging two [Ni(cyclam)12+units. In the same paper, we have also reported the equilibrium constants for the reactions [Ni(cyclam)12+ ox2- = [Ni(cyclam)ox] and [Ni(cyclam)12+ = [Ni2(cyclam)20x]2+. [Ni(cyclam)ox] Aqueous solutions of [Ni(cyclam)12+ a r e composed by a n equilibrium mixture involving a square diamagnetic and two octahedral paramagnetic (both cis- and trans-diaquo) species (Chart I), the cis-diaquo complex being present in a very low p e r ~ e n t a g e . ~T h e oxalate anion can coordinate t o [ N i ( ~ y c l a m ) ] ~in+ a bidentate fashion when the tetraazamacrocyclic ligand is arranged in a folded conformation (Chart I, drawing IV), so t h a t only the cis-diaquo
+
+
( I ) (a) Universita di Firenze. (b) Universitat de Valhcia. (c) UniversitB Pierre et Marie Curie. ( 2 ) Battaglia, L. P.; Bianchi, A.; Bonamartini Corradi, A.; Garcia-Espafia, E.; Julve, M.; Micheloni, M. Inorg. Chem. 1988, 27, 4174. (3) Billo, E. J. Inorg. Chem. 1984, 23, 2223.
0020-1669/90/ 1329-0963$02.50/0
Chart I
.N . .
0%
I
I11
I1
IU
U
form ( C h a r t I, drawing 111) exhibits t h e right conformation to allow such a coordination. T h e formation of the oxalato-bridged complex [ N i , ( ~ y c l a m ) ~ o x ]gives ~ + rise, owing to the particular
0 1990 American Chemical Society
